Circuit breaker for spark



Jan. 5, 1937.

A. A. MELCHER ET AL,

CIRCUIT BREAKER FOR SPARK DISTRIBUTORS Fild Oct. 7, 1955 Patented Jan. 5, 1937 UNITED STATES PATENT OFFICE CIRCUIT BREAKER FOR SPARK DISTRIBUTORS Application October 7, 1935, Serial No. 43,814

8 Claims.

Our invention relates to a circuit breaker for the spark distributors of the ignition circuits of internal combustion engines and has for its principal object, the provision of relatively simple, practical and inexpensive means for automatically regulating the period of electrical dwell or contact of the breaker contacts and thereby regulating the periods of saturation of the coil in the primary circuit to correspond with the speed of the gaseous fuel mixture passing through the carburetor of the internal combustion engine, with which the device is associated and the demands of the coil for a constant milliampere output.

In connection with the ignition systems of internal combustion engines, it will be understood that while the engine is running at low or idle speeds, a relatively short contact in the primary circuit produces sufiicient saturation of the coil without oversaturation and that while the engine is running at high speeds, a longer contact is necessary to properly saturate the coil. Oversaturation heats and burns out the coil and the contact points in the distributor head and these objectionable results are eliminated where my im-- proved circuit breaker is used.

It is the magnetizing and demagnetizing of r must be completely saturated or magnetized and in order to do this, the primary circuit must be closed by the contact points for a. sufficient length of time by reason of the fact that the coil will not become magnetized instantaneously. A certain period of time is required. This being true, it will be seen that the spark or secondary current will grow weaker as the speed of the engine increases because the speed of the cam that operates the circuit breaker correspondingly increases, which shortens the time of contact or dwell of the contact points of the primary circuit.

It is one of the purposes of our invention, to

provide simple and emcient means that is autocontacts in the primary circuit, corresponding with the engine speeds, in order to bring about the proper timing of the saturation of the core of the coil.

With the foregoing and other objects in view our invention consists in certain novel features of construction and arrangements of parts that will be hereinafter more fully described and claimed and illustrated in the accompanying drawing in which:

Fig. 1 is a top plan view of a circuit breaker and spark distributor constructed in accordance with our invention.

Fig. 2 is a vertical section taken on the line 2-2 of Fig.1.

Fig. 3 is an enlarged section taken on the line 3-3 of Fig. 1.

Fig. 4 is an enlarged cross section taken on the line 4-4 of Fig. 1.

Fig. 5 is an enlarged plan view of parts of the circuit breaker with dotted lines showing certain of said parts in shifted positions.

Referring by numerals to the accompanying drawing which illustrates a preferred embodiment of our invention, l0 designates a conventional distributor head in which is journaled for rotation the usual shaft ll carrying the timing cam l2.

Arranged for operation in the coventional manner within the head, is the breaker arm [3 that carries a block or shoe I4, which latter is engaged by the faces of cam I2.

Breaker arm carries at its free end the usual contact member l5.

Suitably secured within the distributor head II! to the side of cam I2 and disposed substantially at right angles to the breaker arm I3, is a tubulan housing IS, in which is formed a slot i1, that is approximately 90 in length and which is slightly inclined with respect to the axis of the tube.

Extending through this tube and bearing therein, is a rock shaft l8 and seated therein is a pin or stud i 9 that projects into slot l'l.

Shaft I8 is formed in two parts that are connectedby a tongue and groove slip joint and which latter is located to the rear of the pin or stud l9 that operates in slot I 1. Such construction enables the forward portion of said shaft to move lengthwise independently of the shorter rear portion of said shaft.

Formed in the forward end of shaft I8 is an axial bore 20 that receives the threaded shank 2| of a contact member 22, which latter is adapted to engage contact ll carried by the breaker arm i3.

Mounted on the projecting portion of shank 20, is a nut 23 and which when screwed against the end of shaft I 8, looks the th'--eaded shank 2i carrying contact 22 in adjusted position.

Detachably mounted on the projecting rear end of shaft I8, is a short crank arm 2! and pivotally connected to the outer end of the latter, is a link 25. The lower end of this link is connected to a piston 20 that is mounted for operation within a cylinder 21, the latter being fixedly mounted, preferably to the distributor head.

The downward movement of piston 22, within cylinder 21, is yieldingly resisted by an expansive coil spring 28.

Connected to the lower end of cylinder 21, is one end of a tube 29, the other end being connected to the chamber within a conventional carburetor C between the throttle valve T and the venturi V.

That portion of tube 29 that extends into the carburetor functions as a Pitot tube to control the pressure exerted on the piston 28. In some instances to produce the desired results the pipe 29 may be extended directly into the venturi or at or near the point of highest velocity flow of the gaseous mixture through the carburetor.

When the engine with which our improved circuit breaker is associated is operating at idle speed, the velocity of the air passing through the carburetor is not strong enough to overcome the tension of spring 28, hence piston 26 is at its upper limit of movement and under such conditions the shaft I8 is maintained at its limit of rotary motion toward the righthand, such position being controlled by the pin or stud l9 which occupies the righthand end of the inclined slot H in tubular bearing it.

Under such conditions contact 22 functions as a stop to limit the swinging movement of the breaker arm toward the cam and when contact I 5 is in engagement with contact 22 as illustrated in Fig. 5, the breaker arm is positioned so that the face of the shoe ll carried thereby, is out of engagement with the lower faces of the cam only during those relatively short periods of time that the low faces of the cam are substantially parallel with the contact face of the shoe.

Thus as the cam rotates relatively slowly in accordance with the idle speed of the engine, the high portions of the cam will engage shoe l4 for relatively long periods and during such periods the engagement of the high portions of thecam with the shoe will move breaker arm outward so as to move contact I! away from contact 22.

Thus at low or idling speeds, contact i5 is in engagement with contact 22 for only relatively short periods of time or while the shoe I 4 is directly opposite the low faces of the cam i2, but these time periods of contact, are sumcient to bring about the desired degree of saturation of the coil. I

As the throttle is opened to increase the speed of the engine, the corresponding increase in the velocity of the gaseous fuel mixture to the intake manifold, produces suction through tube 29 so as to draw piston 26 downwardly in its cylinder 21 and through link 25 and crank arm 24 shaft i8 is rotated anti-clockwise and during such movement the foward portion of said shaft will be moved forward through tube It by the engagement of pin or stud IS in the inclined slot l'l. As a result, contact 22 is moved forward so as to function as a stop for limiting the forward swinging movement of the free end of the breaker arm toward the cam and undersuch conditions, the bearing face of shoe I4 is spaced a greater distance apart from the low faces of the cam than when the engine was operating at low or' idle speed.

Thus the shoe I4 is engaged so as to move the free end of the breaker arm outwardly only as the high portions of the cam engage and pass said shoe and as a result, the periods of contact or dwell between the contacts l5 and 22 are correspondingly increased or lengthened, thus maintaining closed circuit for longer periods and consequently enabling the core of the coil to be sufll ciently saturated in accordance with the increased speed of the engine.

In Fig. 5 we have diagrammatically illustrated in dotted lines the relatively narrow are A to indicate the period of time that the shoe I4 is out of contact with the lowface of the cam and during this time period the contacts l5 and 22 are closed so as to close the primary circuit and as the speed of the engine increases and contact 22 is moved forward as hereinbefore described, the breaker arm I! is moved into the position illustrated by dotted lines X in Fig. 1 so that shoe I4 is drawn away from the cam so that it is engaged only by the high portions thereof.

Obviously when the shoe I4 is drawn away from the cam as just described, the periods of contact or dwell by the contacts l5 and 22 are increased so as to automatically bring about the desired longer periods of coil saturation.

As deceleration takes place to decrease the speed of the engine, the suction through tube 29. due to the decrease in velocity of gaseous fuel passing through the carburetor, decreases, thereby enabling spring 28 to function to elevate piston 26 and through link 25 and arm 24, shaft I8 is rotated clockwise and at the same time the forward portion of said rod will be drawn rear 'Q wardly, due to the engagement of stud IS in slot i! so as to permit the free end of the breaker arm to move toward the cam and the periods of contact or dwell between the contacts I! and 22 are decreased to correspond with the decreasing engine speed.

Thus it will be seen that in our improved circuit breaker,-the contact point 22, which in the present type of circuit breakers is stationary, is mounted so as to function as a variable contact point to increase or decrease the gap in the ignition circuit according to the speed of the englue and the demands of the coil for a constant milliampere output and the velocity of the gaseous mixture flowing from the carburetor in the intake manifold, automatically controlling the movement and position of the movable contact point.

The use of our improved circuit breaker enables a higher voltage coil to be used in the ignition system and such condition is especially desirable and advantageous in order to that it produces the desired results particularly at high engine speeds.

It will be understood that the forward movement of the shaft or plunger l8, which is accomplished by throttle control, the timing of the engine automatically changes, namely, it is retarded, and when accelerating the engine suddenly or when the engine is operating on a heavy lugging pull, such retarding action is of great advantage, particularly in the present high compression motors.

The conventional types of automatic timing control devices may be easily changed to compensate for this retarding action and thus our improved device may be advantageously employed in connection with the present forms of automatictimers and ignition devices.

A further advantage gained by our improved construction is smoothness 01' running the engine at idle speeds with the use of a greater advance spark due to the correct period oi dwell of contact to produce the proper degree of coil saturation. Thus it will be seen that we have provided a circuit breaker for spark distributors that is relatively simple in construction, inexpensive oi. manufacture and.very eiiective in periorming the functions for which'it is intended.

It will be understood that minor changes in the size, form, and construction, oi the various parts of our improved circuit breaker for spark distributors may be made and substituted for those herein shown and described without departing from the spirit of the invention, the scope of which is set forth in the appended claims.

We claim as our invention:

1. In a circuit breaker for .spark distrilmtors including a cam, breaker arm and contact carried by said breaker arm. a contact with which the contact on the bmker arm is adapted to engage and automatically operating means controlled by the velocity flow of the gas air mixy ture through the carburetor with which the circuit breaker is associated, for moving said second mentioned contact toward the contact carried by said breaker arm to increase the periods of contact or dwell between said contacts.

2. In a circuit breaker for spark distributors including a cam, breaker arm and contact carried by said breaker arm, a contact with which thecontactonthebreakerarmisadaptedtoengage and automatically operating means controlled by the velocity flow oi the gas air mixture through the carburetor with which the circuit breaker is associated, for moving said second mentioned contact away from the contact carried by said breaker arm to decrease the periods of contact or dwell between said contacts.

' 3. In a' circuit breaker for spark distributors including a cam, breaker arm and contact carried by said breaker arm, a contact'with which the contact on the breaker arm is adapted to engage and automatically operating means. controlled by the velocity flow of the gas air mixture through the carburetor with which the circuit breaker is associated for moving said second mentioned contact toward and away from the contact carried by the breaker arm to increase or decrease the periods of contact or dwell between said contacts.

4. Means for regulating the time periods of saturation of the coil core or an internal combustion engine ignition system to correspond with the speed or the engine, comprising in combination with a circuit breaker cam, breaker arm gas air mixture through the carburetor oi the engine for moving said second mentioned contact toward and away from the contact carriedby said breaker arm.

5. In a device of the class described, the combination with the cam and breaker arm of a spark distributor circuit breaker, which breaker arm carries a' contact, of a contact mounted for movement toward and away from the contact carried by said breaker arm and. means controlled and actuated by the velocity flow of the air gas mixture through the carburetor of the engine with which the device is associated, for shifting .the position of said second mentioned contact.

6. In a device or the class described, the combination with the cam and breaker arm of a spark distributor circuit breaker, which breaker arm carries a contact, oi a member mounted for movement toward and away from the end of the breaker arm carrying the contact, a contact carried by said member and adapted to engage the contact carried by said breaker arm and means controlled and actuated by the velocity flow of the air gas mixture through the carburetor oi the engine with which the device is' associated for moving said contact carrying member toward a the contact carried by said breaker arm.

7. In a device oi the class descri the combination with the cam and breaker arm of a spark distributor circuit breaker, which .breaker arm carries a contact, of a member mounted for move ment toward and away from the end of the breaker arm carrying the contact, a contact adjustabiy mounted on said member and adapted to engage the contact carried by said breaker arm and means controlled and actuated by the velocity flow oi the air gas mixture through the carburetor oi the engine with which the device is associated for moving said contact carrying member toward the contact carried by said breaker arm.

8. In a device of the class described. the combination with the cam and breaker arm of a spark distributor circuit breaker, which breaker arm carries a contact, of a member mounted for movement toward and away from the end of the breaker arm carrying the contact, a contact carried by said member and adapted to engage the contact carried by said breaker arm, means controlled and actuated by the velocity flow oi the air gas mixture through the carburetor of the engine with which the device is associated for moving said contact carrying member toward the contact carried by said breaker arm and means for moving said contact carrying member away from the contact carried by the breaker arm.

AIJ'RED A. MELCHER- ALBERT G. H. VANDERPO 

